Abstract: Due to the instant destroying process, complexity of the reaction process and high cost of testing, it is very difficult to evaluate laser weapon damage power through experimental approach. Hence, the offensive-defensive performance can be effectively evaluated through numerical simulation of the destructive power. The current work considered the thermal conductivity variation and the melting latent heat when the material phase changed to modify the temperature field. In addition, the corresponding displacement field and stress field model were established and calculated. Finally, multiple physical field models were integrated into a simulation system and the attacking process of target by laser weapon was simulated. Moreover, the damage effect of target on different working conditions was also simulated. The simulation results show that when the laser irradiation of Al material is 3.01 s, the laser real-time power density is 0.930 8 W/cm², the outer wall temperature of the Al material reaches 600℃, and the inner wall temperature is 352.522℃. At this time, the surface of the Al material is just melting, but its stress has made the material brittlely fractured.